Weight-Loss Drugs Linked to Rare, Potentially Fatal Brain Disorder in New Study

A rare and potentially fatal neurological disorder has been identified in individuals taking popular weight-loss medications, according to a recent study.

Wernicke encephalopathy, a condition characterized by severe confusion and disorientation, is caused by a deficiency in thiamine (vitamin B1), which is crucial for brain function. Typically, it affects individuals with alcohol use disorder or other conditions that impair nutrient absorption.

However, a study by Israeli researchers documented 15 cases of Wernicke encephalopathy in people using GLP-1 drugs, a class of medications that includes semaglutide (Ozempic, Wegovy), tirzepatide (Zepbound, Mounjaro), and liraglutide (Saxenda).

The study, published in the journal Clinical Nutrition, found that the average age of affected patients was 59, and they had been taking the drugs for approximately five months before developing symptoms. Common symptoms reported before diagnosis included difficulty walking, confusion, abnormal mental status, and eye muscle weakness.

Researchers suggested that the significant weight loss associated with these drugs, combined with frequent gastrointestinal side effects like vomiting, decreased appetite, and gastroparesis (stomach paralysis), could contribute to nutritional deficiencies, including thiamine depletion.

While the study identified an association, it does not definitively prove that the weight-loss drugs cause the condition. The cases were largely drawn from the FDA's Adverse Event Reporting System, a database where unverified reports can be submitted as an early warning system for potential side effects.

Of the 15 cases, eight involved semaglutide, six involved tirzepatide, and one involved liraglutide. The majority of reports, ten, originated from the US, with others from Europe, Asia, and South America. Four patients had the drugs prescribed for diabetes, three for weight loss, and two for both conditions.

Wernicke encephalopathy is a serious condition that, if left untreated, can lead to irreversible brain damage and memory loss, known as Korsakoff syndrome, and can be fatal.

Treatment typically involves administering vitamin B1 supplements. The researchers emphasized the need for increased clinical awareness among healthcare providers, especially for patients experiencing severe gastrointestinal symptoms while on these medications, to enable early detection and intervention.

Millions of Americans have used weight-loss drugs, and the researchers noted that the identified cases represent a small fraction of the overall user population. The condition has previously been linked to bariatric surgery, which can also lead to malnutrition and thiamine deficiency.